/*-
 * Copyright (c) 2001 Charles Mott <cm@linktel.net>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * $FreeBSD: src/sys/netinet/libalias/alias_local.h,v 1.34.2.1.4.1 2009/04/15 03:14:26 kensmith Exp $
 */

/*
 * Alias_local.h contains the function prototypes for alias.c,
 * alias_db.c, alias_util.c and alias_ftp.c, alias_irc.c (as well
 * as any future add-ons).  It also includes macros, globals and
 * struct definitions shared by more than one alias*.c file.
 *
 * This include file is intended to be used only within the aliasing
 * software.  Outside world interfaces are defined in alias.h
 *
 * This software is placed into the public domain with no restrictions
 * on its distribution.
 *
 * Initial version:  August, 1996  (cjm)
 *
 * <updated several times by original author and Eivind Eklund>
 */

#ifndef _ALIAS_LOCAL_H_
#define _ALIAS_LOCAL_H_

#ifndef VBOX
#include <sys/types.h>
#include <sys/sysctl.h>

#ifdef _KERNEL
#include <sys/malloc.h>
#include <sys/param.h>
#include <sys/lock.h>
#include <sys/mutex.h>

/* XXX: LibAliasSetTarget() uses this constant. */
#define INADDR_NONE 0xffffffff
#endif
#else  /* VBOX */
# include <slirp.h>
#endif /* VBOX */

/* Sizes of input and output link tables */
#define LINK_TABLE_OUT_SIZE        4001
#define LINK_TABLE_IN_SIZE         4001

struct proxy_entry;

struct libalias {
    LIST_ENTRY(libalias) instancelist;

    int     packetAliasMode;    /* Mode flags                      */
    /* - documented in alias.h  */

    struct in_addr  aliasAddress;   /* Address written onto source     */
    /* field of IP packet.           */

    struct in_addr  targetAddress;  /* IP address incoming packets     */
    /* are sent to if no aliasing    */
    /* link already exists           */

    struct in_addr  nullAddress;    /* Used as a dummy parameter for   */
    /* some function calls           */

            LIST_HEAD     (RT_NOTHING, alias_link) linkTableOut[LINK_TABLE_OUT_SIZE];
    /* Lookup table of pointers to     */
    /* chains of link records. Each  */

            LIST_HEAD     (RT_NOTHING, alias_link) linkTableIn[LINK_TABLE_IN_SIZE];
    /* link record is doubly indexed */
    /* into input and output lookup  */
    /* tables.                       */

    /* Link statistics                 */
    int     icmpLinkCount;
    int     udpLinkCount;
    int     tcpLinkCount;
    int     pptpLinkCount;
    int     protoLinkCount;
    int     fragmentIdLinkCount;
    int     fragmentPtrLinkCount;
    int     sockCount;

    int     cleanupIndex;   /* Index to chain of link table    */
    /* being inspected for old links   */
#ifndef VBOX
    int     timeStamp;  /* System time in seconds for      */
    /* current packet                  */

    int     lastCleanupTime;    /* Last time
                         * IncrementalCleanup()  */
#else
    unsigned int     timeStamp;  /* System time in seconds for      */
    unsigned int     lastCleanupTime;    /* Last time */
#endif
    /* was called                      */

    int     deleteAllLinks; /* If equal to zero, DeleteLink()  */
    /* will not remove permanent links */

    /* log descriptor        */
#ifdef  _KERNEL
    char           *logDesc;
#else
    FILE           *logDesc;
#endif
    /* statistics monitoring */

    int     newDefaultLink; /* Indicates if a new aliasing     */
    /* link has been created after a   */
    /* call to PacketAliasIn/Out().    */

#ifndef NO_FW_PUNCH
    int     fireWallFD; /* File descriptor to be able to   */
    /* control firewall.  Opened by    */
    /* PacketAliasSetMode on first     */
    /* setting the PKT_ALIAS_PUNCH_FW  */
    /* flag.                           */
    int     fireWallBaseNum;    /* The first firewall entry
                         * free for our use */
    int     fireWallNumNums;    /* How many entries can we
                         * use? */
    int     fireWallActiveNum;  /* Which entry did we last
                         * use? */
    char           *fireWallField;  /* bool array for entries */
#endif

    unsigned int    skinnyPort; /* TCP port used by the Skinny     */
    /* protocol.                       */

    struct proxy_entry *proxyList;

    struct in_addr  true_addr;  /* in network byte order. */
    u_short     true_port;  /* in host byte order. */
#if defined(_KERNEL) && !defined(VBOX)
    /*
     * avoid races in libalias: every public function has to use it.
     */
    struct mtx mutex;
#endif
#ifdef VBOX
    PNATState pData;
#endif
};

/* Macros */

#if defined(_KERNEL) && !defined(VBOX)
#define LIBALIAS_LOCK_INIT(l) \
        mtx_init(&l->mutex, "per-instance libalias mutex", NULL, MTX_DEF)
#define LIBALIAS_LOCK_ASSERT(l) mtx_assert(&l->mutex, MA_OWNED)
#define LIBALIAS_LOCK(l) mtx_lock(&l->mutex)
#define LIBALIAS_UNLOCK(l) mtx_unlock(&l->mutex)
#define LIBALIAS_LOCK_DESTROY(l)    mtx_destroy(&l->mutex)
#else
#define LIBALIAS_LOCK_INIT(l)
#define LIBALIAS_LOCK_ASSERT(l)
#define LIBALIAS_LOCK(l) NOREF((l));
#define LIBALIAS_UNLOCK(l) NOREF((l))
#define LIBALIAS_LOCK_DESTROY(l)
#endif

/*
 * The following macro is used to update an
 * internet checksum.  "delta" is a 32-bit
 * accumulation of all the changes to the
 * checksum (adding in new 16-bit words and
 * subtracting out old words), and "cksum"
 * is the checksum value to be updated.
 */
#define ADJUST_CHECKSUM(acc, cksum) \
    do { \
        acc += cksum; \
        if (acc < 0) { \
            acc = -acc; \
            acc = (acc >> 16) + (acc & 0xffff); \
            acc += acc >> 16; \
            cksum = (u_short) ~acc; \
        } else { \
            acc = (acc >> 16) + (acc & 0xffff); \
            acc += acc >> 16; \
            cksum = (u_short) acc; \
        } \
    } while (0)


/* Prototypes */

/*
 * We do not calculate TCP checksums when libalias is a kernel
 * module, since it has no idea about checksum offloading.
 * If TCP data has changed, then we just set checksum to zero,
 * and caller must recalculate it himself.
 * In case if libalias will edit UDP data, the same approach
 * should be used.
 */
#ifndef _KERNEL
u_short     IpChecksum(struct ip *_pip);
u_short     TcpChecksum(struct ip *_pip);
#endif
void
DifferentialChecksum(u_short * _cksum, void * _new, void * _old, int _n);

/* Internal data access */
struct alias_link *
FindIcmpIn(struct libalias *la, struct in_addr _dst_addr, struct in_addr _alias_addr,
    u_short _id_alias, int _create);
struct alias_link *
FindIcmpOut(struct libalias *la, struct in_addr _src_addr, struct in_addr _dst_addr,
    u_short _id, int _create);
struct alias_link *
FindFragmentIn1(struct libalias *la, struct in_addr _dst_addr, struct in_addr _alias_addr,
    u_short _ip_id);
struct alias_link *
FindFragmentIn2(struct libalias *la, struct in_addr _dst_addr, struct in_addr _alias_addr,
    u_short _ip_id);
struct alias_link *
        AddFragmentPtrLink(struct libalias *la, struct in_addr _dst_addr, u_short _ip_id);
struct alias_link *
        FindFragmentPtr(struct libalias *la, struct in_addr _dst_addr, u_short _ip_id);
struct alias_link *
FindProtoIn(struct libalias *la, struct in_addr _dst_addr, struct in_addr _alias_addr,
    u_char _proto);
struct alias_link *
FindProtoOut(struct libalias *la, struct in_addr _src_addr, struct in_addr _dst_addr,
    u_char _proto);
struct alias_link *
FindUdpTcpIn(struct libalias *la, struct in_addr _dst_addr, struct in_addr _alias_addr,
    u_short _dst_port, u_short _alias_port, u_char _proto, int _create);
struct alias_link *
FindUdpTcpOut(struct libalias *la, struct in_addr _src_addr, struct in_addr _dst_addr,
    u_short _src_port, u_short _dst_port, u_char _proto, int _create);
struct alias_link *
AddPptp(struct libalias *la, struct in_addr _src_addr, struct in_addr _dst_addr,
    struct in_addr _alias_addr, u_int16_t _src_call_id);
struct alias_link *
FindPptpOutByCallId(struct libalias *la, struct in_addr _src_addr,
    struct in_addr _dst_addr, u_int16_t _src_call_id);
struct alias_link *
FindPptpInByCallId(struct libalias *la, struct in_addr _dst_addr,
    struct in_addr _alias_addr, u_int16_t _dst_call_id);
struct alias_link *
FindPptpOutByPeerCallId(struct libalias *la, struct in_addr _src_addr,
    struct in_addr _dst_addr, u_int16_t _dst_call_id);
struct alias_link *
FindPptpInByPeerCallId(struct libalias *la, struct in_addr _dst_addr,
    struct in_addr _alias_addr, u_int16_t _alias_call_id);
struct alias_link *
FindRtspOut(struct libalias *la, struct in_addr _src_addr, struct in_addr _dst_addr,
    u_short _src_port, u_short _alias_port, u_char _proto);
struct in_addr
        FindOriginalAddress(struct libalias *la, struct in_addr _alias_addr);
struct in_addr
        FindAliasAddress(struct libalias *la, struct in_addr _original_addr);

/* External data access/modification */
int
FindNewPortGroup(struct libalias *la, struct in_addr _dst_addr, struct in_addr _alias_addr,
    u_short _src_port, u_short _dst_port, u_short _port_count,
    u_char _proto, u_char _align);
void        GetFragmentAddr(struct alias_link *_lnk, struct in_addr *_src_addr);
void        SetFragmentAddr(struct alias_link *_lnk, struct in_addr _src_addr);
void        GetFragmentPtr(struct alias_link *_lnk, char **_fptr);
void        SetFragmentPtr(struct alias_link *_lnk, char *fptr);
void        SetStateIn(struct alias_link *_lnk, int _state);
void        SetStateOut(struct alias_link *_lnk, int _state);
int     GetStateIn (struct alias_link *_lnk);
int     GetStateOut(struct alias_link *_lnk);
struct in_addr
        GetOriginalAddress(struct alias_link *_lnk);
struct in_addr
        GetDestAddress(struct alias_link *_lnk);
struct in_addr
        GetAliasAddress(struct alias_link *_lnk);
struct in_addr
        GetDefaultAliasAddress(struct libalias *la);
void        SetDefaultAliasAddress(struct libalias *la, struct in_addr _alias_addr);
u_short     GetOriginalPort(struct alias_link *_lnk);
u_short     GetAliasPort(struct alias_link *_lnk);
struct in_addr
        GetProxyAddress(struct alias_link *_lnk);
void        SetProxyAddress(struct alias_link *_lnk, struct in_addr _addr);
u_short     GetProxyPort(struct alias_link *_lnk);
void        SetProxyPort(struct alias_link *_lnk, u_short _port);
void        SetAckModified(struct alias_link *_lnk);
int     GetAckModified(struct alias_link *_lnk);
int     GetDeltaAckIn(struct ip *_pip, struct alias_link *_lnk);
int     GetDeltaSeqOut(struct ip *_pip, struct alias_link *_lnk);
void        AddSeq    (struct ip *_pip, struct alias_link *_lnk, int _delta);
void        SetExpire (struct alias_link *_lnk, int _expire);
void        ClearCheckNewLink(struct libalias *la);
void        SetProtocolFlags(struct alias_link *_lnk, int _pflags);
int     GetProtocolFlags(struct alias_link *_lnk);
void        SetDestCallId(struct alias_link *_lnk, u_int16_t _cid);

#ifndef NO_FW_PUNCH
void        PunchFWHole(struct alias_link *_lnk);

#endif

/* Housekeeping function */
void        HouseKeeping(struct libalias *);

/* Tcp specfic routines */
/* lint -save -library Suppress flexelint warnings */

/* Transparent proxy routines */
int
ProxyCheck(struct libalias *la, struct ip *_pip, struct in_addr *_proxy_server_addr,
    u_short * _proxy_server_port);
void
ProxyModify(struct libalias *la, struct alias_link *_lnk, struct ip *_pip,
    int _maxpacketsize, int _proxy_type);

enum alias_tcp_state {
    ALIAS_TCP_STATE_NOT_CONNECTED,
    ALIAS_TCP_STATE_CONNECTED,
    ALIAS_TCP_STATE_DISCONNECTED
};

#if defined(_NETINET_IP_H_)
static __inline void *
ip_next(struct ip *iphdr)
{
    char *p = (char *)iphdr;
    return (&p[iphdr->ip_hl * 4]);
}
#endif

#if defined(_NETINET_TCP_H_)
static __inline void *
tcp_next(struct tcphdr *tcphdr)
{
    char *p = (char *)tcphdr;
    return (&p[tcphdr->th_off * 4]);
}
#endif

#if defined(_NETINET_UDP_H_)
static __inline void *
udp_next(struct udphdr *udphdr)
{
    return ((void *)(udphdr + 1));
}
#endif

#endif              /* !_ALIAS_LOCAL_H_ */
